The approach to landing and touch down on the runway of an aircraft is probably the most challenging task a pilot undertakes during normal operation. To perform the landing properly, the aircraft approaches the runway within an envelope of attitude, course, speed, and rate of descent limits. The course limits include, for example, both lateral limits and glide slope limits (vertical). An approach outside of this envelope can result in an undesirable positioning of the aircraft with respect to the runway, resulting in possibly discontinuance of the landing attempt.
In some instances visibility may be poor during approach and landing operations, resulting in what is known as instrument flight conditions. During instrument flight conditions, pilots rely on instruments, rather than visual references, to navigate the aircraft. Even during good weather conditions, pilots typically rely on instruments during the approach to some extent. Many airports and aircraft include instrument landing systems (ILS) to help guide aircraft during approach and landing operations. These systems allow for the display of a lateral deviation indicator to indicate aircraft lateral deviation from the approach course, and the display of a glide slope indicator to indicate vertical deviation from the glide slope.
Typical instrumentation of an aircraft primary flight display shows the heading by an arrow pointing on a compass and may include an aircraft symbol pointing in the direction in which the aircraft is going. The aircraft symbol may be displayed relative to a geometric symbol or set of symbols, to indicate whether the aircraft is left or right of the desired course and above, below, or on the desired glide slope.
Although these known aircraft systems, including those described immediately above, are generally safe, reliable, and robust, these systems do suffer certain drawbacks. When pilots fly course intercept in VFR/IFR conditions, it is often difficult to judge the path in three dimension space to properly intercept the course line due to the aircraft being at an altitude above the ground course line to the target runway. For example, when turning onto a runway centerline for final approach in typical GPS approaches, aircraft may overshoot or undershoot the runway centerline. This is more of an issue in IMC conditions when the runway is not in sight. For an ILS approach course capture, the interval from ILS deviation becoming valid to the capture of beam center is relatively short due to narrower beam width which can lead to overshoot or less desirable turn maneuvers. Given the trend of tighter path management for increased capacity, particularly within terminal airspace, it is desirable to provide an intuitive intercept pathway display that is compatible with aircraft parameters for proper course line intercept.
Accordingly, it is desirable to provide an aircraft navigation instrumentation system and more particularly to displaying a flight path for intercepting an instrument approach path. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.